[ANALYZER-2390] - Axis scale chart option only affects inner ring values in Sunburst chart.

* Handling the displayUnits option in the Sunburst chart.
* Added a central _parseDisplayUnits method, parses displayUnits and displayUnitsSecondary, for every chart (not only Sunburst). This is now used by the already existing _configureAxisDisplayUnits method.
* Replaced legacy use of dimension.sum by dimension.value.
* Renamed existing _configureAxesDisplayUnits to _configureDisplayUnits, to better handle the Sunburst case, where the axis concept is not explicit.
* Fixed one or two indentation problems (including margin-aligned single comments, which mess up code outlining in some editors)

This pull-request is dependent on https://github.com/webdetails/ccc/pull/71.

@pamval please review.